Single cell and energy storage device

Abstract

The application discloses a single battery and an energy storage device. The single battery comprises a shell, a pole piece assembly, an insulating film and a constraint, the shell is provided with an accommodation space, the shell comprises two first side walls and two second side walls, the two first side walls are arranged at intervals, the two second side walls are connected between the two first side walls and surround the accommodation space, and the area of the first side wall is larger than that of the second side wall; the pole piece assembly is arranged in the accommodation space; the insulating film wraps the pole piece assembly; and the constraint is connected between the two first side walls and is used for limiting the relative deformation between the two first side walls. In the above embodiment, since the single battery is prone to expansion in the direction perpendicular to the first side wall, the two first side walls with larger areas are connected through the constraint, the relative expansion deformation of the shell caused by the change of internal pressure during the charging and discharging process can be effectively limited, the structural stability of the battery is improved, and the cycle life of the single battery is prolonged.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to a single-cell battery and an energy storage device. Background Technology

[0002] A single-cell battery is a basic electrochemical unit that converts electrical energy into chemical energy for storage and vice versa. During repeated charge and discharge cycles, single-cell batteries are prone to expansion and deformation, affecting their normal operation and lifespan. The larger the single-cell battery, the greater the expansion and deformation of its electrode components tends to be, making it difficult for the battery casing to support this deformation and potentially leading to thermal runaway. Therefore, effectively suppressing the expansion and deformation of single-cell batteries has become a key technical problem to be solved. Summary of the Invention

[0003] This application provides a single-cell battery and an energy storage device.

[0004] The single-cell battery of this application includes a casing, an electrode assembly, an insulating film, and a constraint member. The casing has a receiving space and includes two first sidewalls and two second sidewalls. The two first sidewalls are spaced apart, and the two second sidewalls are connected between the two first sidewalls and enclose the receiving space. The area of ​​the first sidewalls is larger than the area of ​​the second sidewalls. The electrode assembly is disposed within the receiving space. The insulating film covers the electrode assembly. The constraint member connects the two first sidewalls and is used to limit the relative deformation between the two first sidewalls.

[0005] In the above embodiments, since individual cells are prone to expansion in the direction perpendicular to the first sidewall, connecting the two large-area first sidewalls with a constraint member can effectively limit the relative expansion deformation of the casing caused by internal pressure changes during charging and discharging, improve the stability of the battery structure, and extend the cycle life of individual cells.

[0006] In some embodiments, the constraint is at least partially located within the receiving space and extends from one of the first sidewalls to the other first sidewall, with a first end of the constraint embedded in one of the first sidewalls and a second end embedded in the other first sidewall.

[0007] In the above embodiment, the constraint component is located within the accommodating space and connects to the two first sidewalls. It can directly act on the easily deformable areas of the first sidewalls, enhancing the suppression effect on shell deformation, while avoiding the space occupation problem caused by the constraint component being completely external. The embedded connection at both ends of the constraint component achieves integrated fixation with the sidewalls, improving the compactness of the connection between the constraint component and the shell, making the single battery cell more compact.

[0008] In some embodiments, one of the first sidewalls is provided with a first mounting hole, and the other first sidewall is provided with a second mounting hole, wherein a first end of the constraint member passes through the first mounting hole and a second end passes through the second mounting hole.

[0009] In the above embodiments, the installation of the constraint components is achieved through mounting holes, which simplifies the installation process and ensures positioning accuracy. This allows the constraint components to evenly distribute the force on the sidewalls and avoids damage to the shell caused by local stress concentration.

[0010] In some embodiments, the first mounting hole includes a through hole and a countersunk hole connected to the through hole, the countersunk hole communicating with the outer surface of the first sidewall, the diameter of the countersunk hole being larger than the diameter of the through hole, the constraint member including a connecting rod and a limiting head disposed at one end of the connecting rod, the limiting head being housed in the countersunk hole, the connecting rod passing through the through hole, and the end of the connecting rod away from the limiting head forming the second end of the constraint member.

[0011] In the above embodiments, the design of the countersunk hole and the limiting head enables the concealed installation of the constraint component, avoiding the space occupied by the protruding structure.

[0012] In some embodiments, the end face of the limiting head is flush with or recessed relative to the outer surface of the first sidewall.

[0013] In the above embodiments, the non-protruding design of the limiting head ensures the flatness of the shell surface, facilitates the stacking and bonding of multiple individual batteries, eliminates the risk of assembly interference caused by exposed limiting heads, and further improves the efficiency of automated assembly and structural consistency of the production line.

[0014] In some embodiments, the first end and / or the second end of the constraint member is welded to the corresponding first sidewall.

[0015] In the above embodiments, welding and fixing further strengthens the connection strength between the constraint and the first sidewall, effectively resists repeated stress impacts during the charge and discharge cycles of a single battery, prevents the constraint from loosening and failing, and ensures long-term reliability.

[0016] In some embodiments, the number of the constraint members is multiple, and the multiple constraint members are arranged at intervals.

[0017] In the above embodiments, multiple spaced constraint members form a multi-point support structure, which can evenly distribute the deformation stress of the shell and improve the overall structure's resistance to deformation.

[0018] In some embodiments, the constraint element passes through the electrode assembly and the insulating film.

[0019] In the above embodiments, the constraint member passes through the electrode assembly and the insulating film, which can constrain the easily deformable areas of the shell and simultaneously apply a reverse constraint force when the cell expands, thereby suppressing the displacement and deformation of the electrode assembly.

[0020] In some embodiments, the constraint includes a connecting rod and an insulating layer sleeved around the outer periphery of the connecting rod, both the connecting rod and the insulating layer passing through the electrode assembly, and the insulating layer isolating the connecting rod from the electrode assembly.

[0021] In the above embodiments, the insulating layer effectively isolates the connecting rod from the electrode assembly, avoiding the risk of internal short circuits caused by contact between metal parts, while not affecting the structural support function of the constraint component, thus balancing safety and structural stability.

[0022] This application also provides an energy storage device comprising at least one of the aforementioned single-cell batteries.

[0023] In the above embodiments, a single battery cell with an anti-deformation structure is used to maintain the structural stability of the energy storage device during long-term charge-discharge cycles, reduce the risk of module deformation or thermal runaway caused by the expansion of the single battery cell, and improve the safety and service life of the overall system.

[0024] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0025] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, wherein: Figure 1 This is a three-dimensional schematic diagram of a single battery cell according to an embodiment of this application; Figure 2 This is a side view of a single battery cell according to an embodiment of this application; Figure 3 yes Figure 2 A schematic cross-sectional view of a single cell along direction II; Figure 4 yes Figure 3 A partial schematic diagram of a single cell; Figure 5 This is a perspective view of the constraint element according to an embodiment of this application; Figure 6 This is a cross-sectional schematic diagram of the constraint element according to an embodiment of this application; Figure 7 yes Figure 3 An enlarged schematic diagram of part A of a single cell; Figure 8 This is a schematic diagram of the energy storage system according to an embodiment of this application.

[0026] Explanation of reference numerals in the attached figures: 100 - Single cell, 10 - Casing, 101 - Accommodation space, 11 - First sidewall, 111 - First mounting hole, 1111 - Through hole, 1112 - Countersunk hole, 112 - Second mounting hole, 12 - Second sidewall, 20 - Electrode assembly, 21 - First electrode, 22 - Second electrode, 23 - Separator layer, 30 - Constraint, 31 - First end, 32 - Second end, 33 - Connecting rod, 34 - Limiting head, 35 - Insulating layer, 40 - Insulating film, 400 - Energy storage system, 410 - High voltage cable, 420 - First power conversion device, 430 - Second power conversion device, 440 - Energy storage device. Detailed Implementation

[0027] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0028] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0029] The following disclosure provides many different embodiments or examples for implementing different structures of this application. To simplify the disclosure, specific examples and settings are described below. Of course, these are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or settings discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0030] Please see Figures 1-3The single-cell battery 100 includes a housing 10, an electrode assembly 20, an insulating film 40, and a restraining member 30. The housing 10 has a receiving space 101 and includes two first sidewalls 11 and two second sidewalls 12. The two first sidewalls 11 are spaced apart, and the two second sidewalls 12 are connected between the two first sidewalls 11 and enclose the receiving space 101. The area of ​​the first sidewalls 11 is larger than the area of ​​the second sidewalls 12. The electrode assembly 20 is disposed in the receiving space 101. The insulating film 40 covers the electrode assembly 20. The restraining member 30 connects the two first sidewalls 11 and is used to limit the relative deformation between the two first sidewalls 11.

[0031] In the above embodiment, since the single cell 100 is prone to expansion in the direction perpendicular to the first sidewall 11, the two first sidewalls 11 with larger areas are connected by the constraint member 30, which can effectively limit the relative expansion deformation of the casing 10 caused by internal pressure changes during charging and discharging, improve the stability of the battery structure, and extend the cycle life of the single cell 100.

[0032] In the above embodiments, the single cell 100 includes, but is not limited to, secondary batteries such as lithium-ion batteries, sodium-ion batteries, and potassium-ion batteries. Its core function is to realize the mutual conversion of electrical energy and chemical energy through electrochemical reactions, and it is widely used in energy storage systems, electric vehicles and other fields.

[0033] The housing 10 is enclosed by two first sidewalls 11 and two second sidewalls 12 to form an accommodating space 101, wherein the area of ​​the first sidewalls 11 is larger than the area of ​​the second sidewalls 12, and a rectangular or approximately rectangular structure can be formed. The four sidewalls of the housing 10 together form a closed cavity, providing physical protection and boundary constraint for the electrode assembly 20. The housing 10 can be made of aluminum alloy, stainless steel, or high-strength engineering plastic, providing sealing performance and structural support, preventing electrolyte leakage and protecting the internal electrode assembly 20.

[0034] The electrode assembly 20 is disposed in the receiving space 101 of the housing 10. The electrode assembly 20 can be formed by stacking or winding positive electrode, negative electrode and separator, and is the core component for the electrochemical reaction of the battery. During charging and discharging, the electrode assembly 20 will expand in volume due to lithium ion insertion or deintercalation, mainly exerting expansion force in the direction of the larger first sidewall 11.

[0035] The insulating film 40 covers the outer surface of the electrode assembly 20 to reduce the risk of short circuit between the electrode assembly 20 and the housing 10. The insulating film 40 can be Mylar (polyester film).

[0036] The constraint member 30 can be made of metal rod, carbon fiber rod, or high-strength composite material, and its two ends are respectively connected to the two first sidewalls 11. The connection can be achieved by embedding, welding, or bolting. The constraint member 30 can provide rigid support, restricting the relative deformation of the first sidewalls 11 when the electrode assembly 20 expands, and maintaining the stability of the battery structure. When the electrode assembly 20 expands and causes the first sidewalls 11 to bulge outward, the constraint member 30 provides a reverse tensile force through its own rigidity to offset part of the expansion stress, thereby reducing the deformation of the housing 10.

[0037] In the embodiments of this application, "first sidewall" and "second sidewall" are used only to distinguish between two types of sidewalls with different areas on the shell 10, and do not indicate any special meaning of position or order.

[0038] In some implementations, please refer to Figure 3 The constraint member 30 is at least partially located in the receiving space 101 and extends from one of the first sidewalls 11 to the other first sidewall 11. A first end 31 of the constraint member 30 is embedded in one of the first sidewalls 11 and a second end 32 is embedded in the other first sidewall 11.

[0039] In the above embodiment, the constraint member 30 is partially located in the accommodating space 101 and connects to the two first sidewalls 11. It can directly act on the easily deformable areas of the first sidewalls 11, enhancing the suppression effect on the deformation of the housing 10, while avoiding the space occupation problem caused by the constraint member 30 being completely external. The embedded connection at both ends of the constraint member 30 achieves integrated fixation with the sidewalls, improving the compactness of the connection between the constraint member 30 and the housing 10, making the single battery 100 more compact.

[0040] In the above embodiment, the constraint member 30 adopts a partially built-in design, that is, part of the structure is located in the receiving space 101, and another part can extend to the outside of the housing 10 or be completely built-in. This layout ensures direct action on the deformation area of ​​the first sidewall 11 while avoiding the space occupation problem when it is completely external, thus improving the compactness of the single cell 100. The constraint member 30 extends from one first sidewall 11 to the other first sidewall 11, forming a rigid support beam structure spanning the receiving space 101. The extension path of the constraint member 30 can be optimized according to the expansion stress distribution of the electrode assembly 20, for example, arranged along the length or width direction of the housing 10, preferentially covering the area with the largest deformation (such as the middle of the housing 10).

[0041] "Embedding" refers to a connection method in which the end of the constraint member 30 is fixed inside the first sidewall 11 through a preset structure (such as a mounting hole or groove), so that the constraint member 30 and the first sidewall 11 form an integrated structure with mechanical engagement or physical embedding. The embedding structure makes the end of the constraint member 30 rigidly connected to the first sidewall 11. When the electrode assembly 20 expands and squeezes the first sidewall 11, the deformation force of the first sidewall 11 is directly transmitted to the constraint member 30. The constraint member 30 provides a reverse support force through its own stiffness, effectively suppressing the outward bulging of the first sidewall 11.

[0042] In other embodiments, the aforementioned constraint member 30 may also be disposed on the outside of the housing 10. For example, the constraint member 30 may be connected to the two first sidewalls 11 by means of clamping, thereby limiting the deformation of the two first sidewalls 11.

[0043] Please see Figures 3 to 5 In some embodiments, one of the first sidewalls 11 is provided with a first mounting hole 111, and the other first sidewall 11 is provided with a second mounting hole 112. The first end 31 of the constraint member 30 passes through the first mounting hole 111, and the second end 32 passes through the second mounting hole 112.

[0044] In the above embodiments, the constraint member 30 is installed through the mounting hole, which simplifies the installation process and ensures the positioning accuracy. This allows the constraint member 30 to evenly distribute the force on the side wall and avoid damage to the shell 10 caused by local stress concentration.

[0045] In the above embodiment, the first mounting hole 111 and the second mounting hole 112 are respectively formed on two opposite first sidewalls 11, and the hole diameters can form a clearance fit or an interference fit with the diameter of the constraint member 30. The axes of the first mounting hole 111 and the second mounting hole 112 are collinear, ensuring that the force path of the constraint member 30 is straightened after it passes through, minimizing the risk of bending deformation. The mounting holes can be integrally formed with the housing 10 (such as die casting or injection molding), or formed through post-processing (such as drilling or boring).

[0046] The constraint member 30 can be a rod-shaped or tubular structure, with a length slightly greater than the distance between the two first sidewalls 11. After insertion, both ends can be located in the corresponding mounting holes for easy subsequent fixing (such as welding or nut locking). When the mounting hole and the constraint member 30 are clearance-fitted, the space between the constraint member 30 and the mounting hole can be filled with structural adhesive (such as epoxy resin). After curing, a rigid connection is formed, and the mounting hole is sealed to ensure the airtightness of the accommodating space 101.

[0047] The first mounting hole 111 and the second mounting hole 112 can be located in a location that avoids stress concentration areas (such as corners) on the first sidewall 11, and are preferably located in the middle of the first sidewall 11 or in a region near the expansion center of the electrode assembly 20.

[0048] Please see Figure 4 , Figure 6 and Figure 7 In some embodiments, the first mounting hole 111 includes a through hole 1111 and a countersunk hole 1112 connected to the through hole 1111. The countersunk hole 1112 communicates with the outer surface of the first sidewall 11. The diameter of the countersunk hole 1112 is larger than the diameter of the through hole 1111. The constraint member 30 includes a connecting rod 33 and a limiting head 34 disposed at one end of the connecting rod 33. The limiting head 34 is housed in the countersunk hole 1112. The connecting rod 33 passes through the through hole 1111. The end of the connecting rod 33 away from the limiting head 34 forms the second end 32 of the constraint member 30.

[0049] In the above embodiment, the design of the countersunk hole 1112 and the limiting head 34 enables the concealed installation of the constraint member 30, avoiding the space occupied by the protruding structure.

[0050] In the above embodiment, the through hole 1111 and the countersunk hole 1112 are coaxial stepped hole structures. The diameter of the countersunk hole 1112 is larger than that of the through hole 1111, and the countersunk hole 1112 forms an annular stepped surface for the positioning head 34 to sit on. The diameter of the through hole 1111 and the connecting rod 33 can be fitted with a clearance to ensure that the connecting rod 33 can be smoothly inserted.

[0051] The limiting head 34 can be circular or hexagonal, with a thickness roughly the same as the depth of the countersunk hole 1112. Its diameter can be slightly smaller than the countersunk hole 1112 for precise placement. The diameter of the connecting rod 33 matches the through hole 1111, and the length of the connecting rod 33 can be equal to the distance between the two first sidewalls 11 plus twice the depth of the countersunk hole 1112, ensuring reliable fixation at both ends. The limiting head 34 and the connecting rod 33 can be integrally formed (e.g., turned, forged), and the material can be a high-strength alloy.

[0052] In the embodiments of this application, the "connecting rod" is the main rod-shaped structure of the constraint member 30, and the "limiting head" is an enlarged diameter structure disposed at one end of the connecting rod 33. Together, they constitute the constraint member 30.

[0053] Please see Figure 7 In some embodiments, the end face of the limiting head 34 is flush with or recessed relative to the outer surface of the first sidewall 11.

[0054] In the above embodiments, the non-protruding end face design of the limiting head 34 ensures the flatness of the housing 10 surface, which facilitates the stacking and bonding of multiple single cells 100, eliminates the risk of assembly interference caused by the exposed limiting head 34, and further improves the automated assembly efficiency and structural consistency of the production line.

[0055] In the above embodiments, "the end face of the limiting head 34 is flush with the outer surface of the first side wall 11" means that the end face of the limiting head 34 and the outer surface of the first side wall 11 are on the same plane, and "recessed relative to the outer surface of the first side wall 11" means that the end face of the limiting head 34 is recessed inward relative to the outer surface of the first side wall 11 in the direction of the receiving space 101. Both cases can ensure that the constraint member 30 is not exposed on the surface of the housing 10, thus achieving compact installation.

[0056] In this embodiment, the second end 32 of the constraint member 30 refers to the end away from the limiting head 34. The second end 32 does not have a limiting head 34, and its end shape can be the cross-sectional shape of the connecting rod 33 (such as a circular cross-section end face). This facilitates the insertion of the constraint member 30 from the outside of the first sidewall 11 along the first mounting hole 111 and through the receiving space 101 during assembly. After the second end 32 passes through the second mounting hole 112 on the other side of the first sidewall 11, it is fixedly connected to the first sidewall 11 by welding. It can be understood that the asymmetrical structure with only the limiting head 52 on the first end 31 provides clear guidance for the constraint member 30 in the insertion direction, simplifying the assembly operation. Simultaneously, the welding and fixing of the second end 32 also restricts the outward deformation of the first sidewall 11.

[0057] Please see Figure 4 In some embodiments, the first end 31 and / or the second end 32 of the constraint member 30 are welded to the corresponding first sidewall 11.

[0058] In the above embodiments, welding and fixing further strengthens the connection strength between the constraint member 30 and the first sidewall 11, effectively resists repeated stress impacts during the charge and discharge cycles of the single cell battery 100, prevents the constraint member 30 from loosening and failing, and ensures long-term reliability.

[0059] In the above embodiments, depending on the material combination of the constraint member 30 and the first sidewall 11, laser welding (for aluminum alloy or nickel alloy shells) or arc welding (for stainless steel shells) can be used. The welding area can use a full penetration butt weld or a fillet weld, and the weld can continuously surround the end of the constraint member 30 to form a closed loop. The constraint member 30 and the first sidewall 11 can also be fixed in a non-welding manner. For example, the two ends of the constraint member 30 can be provided with a backing structure or external threads, and after being embedded, it can be locked by backing or nut to prevent loosening.

[0060] In some implementations, please refer to Figure 1 and Figure 3 There are multiple constraint members 30, and the multiple constraint members 30 are arranged at intervals.

[0061] In the above embodiment, multiple spaced constraint members 30 form a multi-point support structure, which can evenly distribute the deformation stress of the shell 10 and improve the overall structure's resistance to deformation.

[0062] In the above embodiments, the number of constraint members 30 is determined according to the size of the single cell 100 and the expected expansion force, for example, 2 to 6 can be provided. For large-capacity single cells 100, a staggered arrangement can be used to form a grid-like support to limit the degree of deformation at multiple locations of the single cell 100. The multiple constraint members 30 are preferably arranged in the expansion center region of the electrode assembly 20 and avoid the stress concentration areas at the corners of the housing 10. The multiple constraint members 30 can adopt the same diameter or a differentiated design, for example, the diameter of the central constraint member 30 is larger than the diameter of the edge constraint members 30, to match the non-uniform expansion characteristics of the electrode assembly 20.

[0063] Please see Figure 3 and Figure 4 In some embodiments, the constraint member 30 passes through the electrode assembly 20 and the insulating film 40.

[0064] In the above embodiment, the constraint member 30 passes through the electrode assembly 20 and the insulating film 40, which can constrain the easily deformable areas of the housing 10, thereby applying a reverse constraint force simultaneously when the cell expands, and suppressing the displacement and deformation of the electrode assembly 20.

[0065] In the above embodiment, the constraint member 30 penetrates the electrode assembly 20 and the insulating film 40 along the thickness direction of the electrode assembly 20. When the cell expands, the electrode assembly 20 transmits the expansion force to the constraint member 30 through the two first sidewalls 11. The constraint member 30 can limit the outward bulging of the two first sidewalls 11, thereby reducing the deformation of the two first sidewalls 11. The constraint member 30 can also penetrate the non-active area of ​​the electrode assembly 20 or be arranged along the edge of the housing 10, so as not to interfere with the electrochemical reaction and to act directly on the sidewall deformation area.

[0066] Please see Figure 6 and Figure 7 In some embodiments, the constraint member 30 includes a connecting rod 33 and an insulating layer 35 sleeved on the outer periphery of the connecting rod 33. Both the connecting rod 33 and the insulating layer 35 pass through the electrode assembly 20, and the insulating layer 35 isolates the connecting rod 33 from the electrode assembly 20.

[0067] In the above embodiment, the insulating layer 35 effectively isolates the connecting rod 33 from the electrode assembly 20, avoiding the risk of internal short circuit caused by contact between metal parts, while not affecting the structural support function of the constraint member 30, thus balancing safety and structural stability.

[0068] In the above embodiments, the insulating layer 35 can be made of polyimide (PI) or cross-linked polyethylene (XLPE) and meet the insulation requirements of the single cell 100 within its operating temperature range. The insulating layer 35 and the connecting rod 33 can be integrally molded using a molding process to prevent the insulating layer 35 and the connecting rod 33 from delaminating. The two ends of the insulating layer 35 can be retracted relative to the end faces of the constraint member 30, so that the two ends of the constraint member 30 can more easily and reliably contact and weld with the first sidewall 11, thereby improving the welding strength and the reliability of the interface bonding.

[0069] Please see Figure 3 In some embodiments, the electrode assembly 20 includes a first electrode 21 and a second electrode 22 stacked with the first electrode 21. The first electrode 21 and the second electrode 22 have opposite polarities. Both the first electrode 21 and the second electrode 22 are provided with through holes, and the constraint member 30 passes through the through holes.

[0070] In the above embodiment, through holes are pre-made on the electrode sheets so that the constraint member 30 can directly penetrate each electrode layer, thereby constraining each layer of the electrode assembly 20 and more accurately limiting the expansion and deformation of the electrode assembly 20 during the charging and discharging process.

[0071] In the above embodiment, the first electrode 21 and the second electrode 22 are the positive electrode and the negative electrode, respectively. The positive and negative electrodes are stacked alternately and cooperate with the separator to form the electrode assembly 20. Through holes are formed in the non-coated areas of the positive and negative electrodes (such as the edge area opposite the tab) to avoid affecting the active area of ​​the electrochemical reaction. The diameter of the through holes matches the outer diameter of the constraint member 30 to ensure a reasonable gap between the constraint member 30 and the electrode after insertion, avoiding local stress concentration on the electrode due to excessive rigidity of the constraint member 30.

[0072] In some embodiments, the method of forming the through holes in the electrode assembly 20 can be flexibly selected according to the production process requirements. In some embodiments, the through holes can be precisely prepared in the non-coated areas of the positive and negative electrodes by laser cutting or mechanical punching before the electrode assembly 20 is formed. This method helps to avoid the adverse effects of high-temperature insertion operations on the thermal stability of the separator and the insulation performance of the insulating film 40.

[0073] In the above embodiments, the diaphragm in the final product also has through holes for the constraint member 30 to pass through. These through holes are not formed during the manufacturing of the diaphragm, but are formed in a separate process before the electrode assembly 20 is assembled. The positions of the through holes on the diaphragm correspond to the through holes of the first electrode 21 and the second electrode 22 to ensure that the constraint member 30 can smoothly pass through the entire electrode assembly 20. In some embodiments, the through holes can also be formed by directly piercing the electrode assembly 20 with the heated constraint member 30. In this case, the diaphragm and the insulating film 40 carbonize at the piercing site to form a perforation. When a pre-drilling method is used, the above carbonization process can be omitted. This application does not limit the method of forming the through holes.

[0074] In some embodiments, the manufacturing process of the single cell 100 is as follows: First, through holes are formed on the first electrode 21 and the second electrode 22 of the electrode assembly 20, and the electrode assembly 20 is formed by stacking or winding. Then, an insulating film 40 (such as a Mylar film) is used to completely wrap the outer surface of the electrode assembly 20 to complete the insulation protection. The wrapped electrode assembly 20 is then installed into the housing 10 of the preset receiving space 101. Next, a heated rod is inserted into the housing 10 along the first mounting hole 111 to melt the separator layer 23 and the insulating film 40 of the electrode assembly 20 to form a perforation. Then, a constraint member 30 is inserted into the housing 10 through the first mounting hole 111, and the other end of the constraint member 30 is embedded in the first sidewall 11. Then, the two ends of the constraint member 30 are welded to the corresponding first sidewall 11 by welding. Finally, subsequent processes such as electrolyte injection, encapsulation and formation are performed to complete the assembly of the single cell 100.

[0075] It should be noted that the holes on the diaphragm layer 23 and the insulating film 40 can also be precisely prepared in advance by laser or mechanical means before the electrode assembly 20 is formed, so as to avoid the adverse effects of high temperature perforation on the thermal stability of the diaphragm and the insulation performance of the insulating film 40.

[0076] In the embodiments of this application, "first electrode 21" and "second electrode 22" are used to distinguish between two types of electrodes with opposite polarities, and "first" and "second" do not indicate any special meaning of position or order.

[0077] Please see Figure 8 This application also provides an energy storage device 440, which includes at least one of the aforementioned single-cell batteries 100.

[0078] In the above embodiments, a single cell 100 with an anti-deformation structure is used to enable the energy storage device 440 to maintain structural stability during long-term charge-discharge cycles, reduce the risk of module deformation or thermal runaway caused by the expansion of the single cell 100, and improve the safety and service life of the overall system.

[0079] This application provides an energy storage system 400, which includes a high-voltage cable 410, a first power conversion device 420, a second power conversion device 430, and an energy storage device 440 provided in this application. In some embodiments of the power generation scenario, the second power conversion device 430 can be a wind power conversion device. Since the electricity generated by wind power conversion is volatile, random, and intermittent, the unstable electricity output by the wind power conversion device can be stored in the energy storage device 440 through grid connection. The energy storage device 440 is connected to the high-voltage cable 410 and outputs smooth electricity to supply the power consumption side of the distribution network, realizing peak shaving and frequency regulation, and stable grid operation; or... The wind power conversion device is always connected to the high-voltage cable 410. Under normal power generation conditions, the power output of the wind power conversion device is supplied to the power consumption side of the distribution network through the high-voltage cable. When the current power load is low and the wind power conversion device generates excess power, the excess power is first stored in the energy storage device 440 to improve the problem of new energy power generation and consumption. When the power load is high, the power grid issues an instruction to transmit the power stored in the energy storage device 440 together with the high-voltage cable 410 in grid-connected mode to supply power to the power consumption side. This provides the power grid with multiple services such as peak shaving, frequency regulation, and backup, giving full play to the peak shaving role of the power grid, promoting peak shaving and valley filling, and alleviating the power supply pressure of the power grid.

[0080] In some embodiments on the distribution network side, the first power conversion device 420 can be a photovoltaic panel, and the energy storage device 440 is connected to the high-voltage cable 410 and installed downstream of the high-voltage cable 410 and between the user load. The electrical energy output by the photovoltaic power conversion device is stored in the energy storage device 440, which can respond in a timely manner to act as a backup power source when the power grid / distribution network fails; or, it can provide power supply support to alleviate line congestion when the high-voltage cable 410 transmission line is blocked, and to delay the economic pressure caused by the expansion of the power grid / distribution capacity when the power grid is planned to be expanded.

[0081] Optionally, the first power conversion device 420 may include, but is not limited to, a photovoltaic panel, and the second power conversion device may include, but is not limited to, a wind power conversion device. The first power conversion device 420 and the second power conversion device 430 can convert at least one of solar energy, light energy, wind energy, thermal energy, tidal energy, biomass energy, and mechanical energy into electrical energy.

[0082] Optionally, the energy storage device 440 may include, but is not limited to, energy storage applications such as energy storage power stations, hydropower / thermal / wind power generation systems, solar power generation systems, mobile power systems, smart home systems, or temporary power supply systems, and may also be applied in multiple fields such as data centers, military equipment, aerospace, charging piles, and electric vehicles.

[0083] In the description of the embodiments of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0084] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with the described embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0085] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A single-cell battery, characterized in that, include: The housing has an accommodating space. The housing includes two first sidewalls 11 and two second sidewalls 12. The two first sidewalls are spaced apart, and the two second sidewalls are connected between the two first sidewalls and enclose the accommodating space. The area of ​​the first sidewalls is larger than the area of ​​the second sidewalls. An electrode assembly is disposed within the receiving space; An insulating film is used to wrap the electrode assembly; A constraint member connecting the two first sidewalls is used to limit the relative deformation between the two first sidewalls.

2. The single-cell battery according to claim 1, characterized in that, The constraint member is at least partially located within the receiving space and extends from one of the first sidewalls to the other first sidewall, with a first end of the constraint member embedded in one of the first sidewalls and a second end embedded in the other first sidewall.

3. The single-cell battery according to claim 2, characterized in that, One of the first sidewalls is provided with a first mounting hole, and the other first sidewall is provided with a second mounting hole. The first end of the constraint member passes through the first mounting hole, and the second end passes through the second mounting hole.

4. The single-cell battery according to claim 3, characterized in that, The first mounting hole includes a through hole and a countersunk hole connected to the through hole. The countersunk hole communicates with the outer surface of the first sidewall. The diameter of the countersunk hole is larger than the diameter of the through hole. The constraint member includes a connecting rod and a limiting head disposed at one end of the connecting rod. The limiting head is housed in the countersunk hole. The connecting rod passes through the through hole. The end of the connecting rod away from the limiting head forms the second end of the constraint member.

5. The single-cell battery according to claim 4, characterized in that, The end face of the limiting head does not protrude beyond the outer surface of the first sidewall.

6. The single-cell battery according to claim 2, characterized in that, The first end and / or the second end of the constraint member are welded to the corresponding first sidewall.

7. The single-cell battery according to claim 2, characterized in that, The number of the constraint members is multiple, and the multiple constraint members are arranged at intervals.

8. The single-cell battery according to claim 2, characterized in that, The constraint element passes through the electrode assembly and the insulating film.

9. The single-cell battery according to claim 8, characterized in that, The constraint member includes a connecting rod and an insulating layer sleeved on the outer periphery of the connecting rod. Both the connecting rod and the insulating layer pass through the electrode assembly, and the insulating layer isolates the connecting rod from the electrode assembly.

10. The single-cell battery according to claim 8, characterized in that, The electrode assembly includes a first electrode and a second electrode stacked with the first electrode. The first electrode and the second electrode have opposite polarities. Both the first electrode and the second electrode are provided with through holes, and the constraint member passes through the through holes.

11. An energy storage device, characterized in that, It includes at least one single cell as described in any one of claims 1 to 10.

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